The present invention relates to a safety device for a road planer machine and in particular to apparatus for preventing a planer drum from rotating or the road planer from moving if an access closure door on the housing enclosing the planer drum is not in its normally closed position.
Road planers are large machines having a housing suspended from the frame which carries a rotating planer drum. The housing is enclosed on all sides except for the bottom through which the rotating planer drum protrudes to tear up concrete pavement and prepare it for resurfacing. The rotating planer drum has fingers protruding therefrom which cause the concrete surface to be removed. At least one access closure means such as a door is formed in the housing so that the drum can be serviced and maintained. It is evident that if the drum is rotating when the access closure means is opened a highly dangerous situation exists. If the rotating drum should come in contact with the road surface it may well impel road particles such as concrete pieces or bits at high speeds out of the open access thereby causing injury to persons in the vicinity thereof. In addition, if maintenance personnel happen to be working in front of the open access door and the planer machine for some reason began to move forward, severe injuries could occur to the individuals in front of the open doors.
Therefore, it is important that power be removed from the rotating drum to prevent rotation thereof in the event the access means or doors are opened. It is also important that the machine be disabled from moving forward if the access doors are opened.
Thus, it is an object of the present invention to provide a road planer in which power is automatically removed from the rotating drum to prevent rotation thereof in the event the access closure is not in its normally closed position.
It is also an object of the present invention to remove power from the propulsion means of the road planer in the event that the access closure on the rotating drum housing is not in its normally closed position.
It is still another object of the present invention to set the brakes of the road planer machine so that the machine cannot move forward in the event that the access closure on the housing enclosing the rotating drum is not in its normally closed position.
It is yet another object of the present invention to provide a signal representing the access closure panel not in its normally closed position and utilizing that signal to disable the propulsion system for the road planer, the drum rotation and positioning control system, and other associated active systems such as conveyor belts and to activate the brakes of the road machine.